1. Field of the Invention
This present invention relates to portable electronic devices. More specifically, the present invention relates to hinge clutches employed in portable electronic devices.
2. Description of the Related Art
Portable electronic devices have gained universal acceptance in a variety of applications including, but not limited to, wireless phones, laptop and palmtop computers, cameras as well as entertainment devices. Such applications usually demand durable, lightweight, space-efficient, and ultimately cost effective devices and associated components.
Many portable electronic devices, such as common flip-phones, employ a body member and a separate, foldable lid. The foldable lid is rotationally supported by and attached to the body of the device via at least one clutch hinge mechanism. The clutch hinge allows for manual rotation of the lid from a closed position adjacent the body of the phone to an angular position relative to the phone body to facilitate use of the phone.
Existing clutch hinges, such as face cam clutch mechanisms, typically allow for discreet positioning of the accompanying rotational lid member. One such clutch hinge includes a spring-loaded face cam and cam follower fitted within a cylindrical housing. Either the cam or the cam follower is rigidly connected to the rotational member, such as a flip portion of a wireless phone. During operation, a torque applied to the rotational lid, functions to apply a corresponding torque to the face cam, causing the face cam to rotate and lock into discreet positions with respect to the cam follower. The cam follower compresses or decompresses a spring as the cam rotates relative to the cam follower.
Unfortunately, such movement will often cause unacceptable wear on the hinge housing. Because the housing and components are often made of lightweight and non-durable materials such as ABS or ABS-PC plastic, they often fail well before operating the intended cycles. In addition, the difficulty of inserting the hinge mechanism within the body of the phone may require special tools and procedures. As a consequence, when one of the hinge components fails, the entire assembly is usually discarded and replaced.
Due to the possibility of premature failure, many conventional electronic devices require separate clutch housings for each point of attachment between the housing and the foldable lid. The additional clutch housings facilitate spring-loading of the face cam and cam follower, secure the face cam clutch to the device hinge housing and help to reduce the overall wear of the hinge assembly.
Unfortunately, the need for an additional clutch housing has many shortcomings. The additional clutch housing must be manufactured from durable, relatively expensive materials, which are often unsuitable for very thin-walled designs and are difficult to color. As a result, face cam clutches that employ an additional housing are often excessively bulky and relatively expensive.
Additional clutch housings also require relatively high-tolerance slots in which protrusions, i.e., keys on the cam follower must slide, thereby rotationally fixing the cam follower relative to the additional clutch housing and allowing the cam follower to unduly translate along a longitudinal axis of the clutch. The requisite tolerances represent addition design and manufacturing costs.
In many electronic devices such as flip phones, it is necessary to establish a wire connection between components in the lid and in the housing. Unfortunately, the hinge clutch mechanism when rotated may pinch and even cut such wires, causing failure of the lid-mounted component.
Hence, a need exists in the art for a space-efficient, durable, and cost-effective hinge clutch assembly that allows for discreet positioning of a rotational member relative to housing. Such mechanism should be readily assembled and disassembled without the need for special tools or the need to discard the entire assembly when a component must be replaced. Finally, operation of the mechanism should not interfere with any wire connections extending between the rotational member and the housing.
The need in the art is addressed by the space-efficient and cost-effective hinge clutch assembly of the present invention. In the illustrative embodiment, the inventive hinge clutch assembly is adapted for use with a portable electronic device and facilitates rotational positioning of a lid member relative to the housing of the device. The hinge clutch assembly includes an elongated cam-shaft having one end adaptable for joint rotation with the lid. A cam follower is mounted on the cam-shaft for joint rotation as well as longitudinal movement along the cam-shaft. A separate cam member is restrained from rotation and a compression spring serves to continuously press the cam follower against the cam member. A cylindrically-shaped retaining member is mounted on an end of the cam-shaft and functions to compress the spring against the cam follower.
The retaining member not only maintains the spring in its compressed position, by sliding the retaining member towards the cam follower, it is possible to further compress the spring, thereby reducing the overall length of the hinge assembly. This, in turn, allows the hinge mechanism to be easily disassembled from the housing and later reassembled.
Another aspect of the present invention resides in the use of a separate idler positioned between the retaining member and an attachment arm of the lid. The spring member compresses the retaining member against the idler to maintain its position in the housing. The idler is formed with a non-symmetrical configuration, which fits with a compatible portion of the housing to prevent the idler from rotating relative to the housing. In addition to supporting the retaining member in its proper position, the idler provides the routing for a wire/flexible circuit between the body of the electronic device and the foldable lid. During assembly, the idler may be displaced along its longitudinal axis to allow the foldable lid to be attached to the body of the electronic device.
Another embodiment of the present invention resides in the simplified method of assembly/disassembly of the hinge mechanism within the housing of the electronic device. The hinge clutch mechanism can be manually or automatically pre-assembled by inserting the cam-shaft through the remaining, aligned components, with the retaining member locking the components against separation. Once pre-assembly is complete, the hinge clutch mechanism can be readily inserted as a unit into the electronic device without the need for any special tools.